Ments



(No'Model.) 'l @.M. RADFORD,

MECHANICAL TELEPHONE.-

No. 357,967. Patented Feb. l5., 1887.

UNITED STATES PATENT OFFICE.

CASSIUS M. RADFORD, OF CONCORD, N. H., ASSIGNOR, BY MESNE ASSIGN- MENTS,TO THEOPULAR TELEPHONE COMPANY, OF SAME PLACE.

MECHANICAL TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 357,967, dated February15, 1887.

Application filed March 30, 1886.

T all whom it may concern,.-

Beit known that I, CAssIUs M. RAnroRD,

a citizen of the United States, residing at Oon.

cord, in the county of Merrimac and State of New Hampshire, haveinvented certain new and useful Improvementsin Mechanical rIelephones,of which the following is a specification.

The object of this invention is to add power Within atelephone-transmitter, and also avoid any liability of tearing t'hebutton on the line-Wire through the parchment diaphragm. These resultsare attained by the construction illustrated in the accompanyingdrawings, forming part of this specification, Figure 1 being a sectionalelevation of the improved telephone, and Fig. 2 a sectional plan View ofthe same.

Similar lettersindicate corresponding parts.

The transmitter is composed of front and back boards, respectively, A B,having interposing side boards, C, forming an Octagon. These latter arepreferably made of thin spruce or other vibrating wood and secured tocleats D, to which they may be either tacked or glued, said cleats Dbeing Inortised into the back board, B.

Suitable tightening-keys, E, are provided and secured 'upon the backboard, one for each of the side boards, C. An iron or metal ring, F, issuspended centrally Within the transmitter by suitable Wires, G,radiating therefrom and passing singly, or one through each of the sideboards, over the bridges H, arranged annularly on the outside of thesaid side boards, and int-o and upon the said keys E.

A parchment diaphragm, I, is secured by tacks il to a suitable ring, J,which may be formed of wood and supported upon posts K.

The line-Wire L is passed through the hole b in the back board, B, thering F, and the parchment diaphragm I, where it is fastened to asuitable button, M.

When the transmitter is placed in position ready for use and therequired tension has been applied by the line-wire L to the diaphragm I,the keys E may be turned and the Wires G drawn taut enough to bring thering Serial No. 197,152. (No model.)

F in contact with the diaphragm directly behind the button M, thusrelieving said diaphragm from further strain. If found desirable, awasher, N, may be interposed between the parchment and the ring F, forthe purpose of deadening the metallic ring which is liable to occur fromthe use of the Wires G, especially in windy Weather. The front board, A,may be provided with a mouthpiece, a, extending inward nearly to thediaphragm, for concentrating the sound ofthe voice.

Having describedmyinvention,whatIclaim, and desire to secure by LettersPatent of the United States, is

l. In a telephone-transmitter, the combination, with the front and backboards, of the vibratory side boards, a diaphragm attached to a circularring properly supported upon said back board, the line-wire with itsretaining-button, and radial Wires located back of the diaphragm, oneend of each being secured to a ring surrounding the line-wire, the otherpassing through the side boards over suitable bridges upon the outerside thereof and secured to the back board, substantially as and for thepurpose set' forth.

2. In. a telephone-transmitter constructed substantially as set forth,the combination, with the radiating Wires and their centralretainingring, of the tightening-keys by which the diaphragm may berelieved of any excessive strain by the line-wire, as described.

3. The combination, with the diaphragm and its button, of the line-wire,the suspended adjustable retaining-ring, and a Washer interposed betweensaid ring and diaphragm, as set forth.

4. The combination', with the diaphragm and line-wire, of a series ofvibrating side boards arranged between the front and back boards andentirely surrounding the diaphragm, as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

CASSIUS M. RADFORD.

Witnesses:

J. B. THURsToN, NATHANIEL E. MARTIN.

